The present invention is directed to environmental control systems, and especially to environmental control systems affecting environmental conditions in a plurality of spaces and controlled using a network arrangement.
Environmental control networks generally include a central control unit coupled by a network with a plurality of variable air volume units in air ducts serving various conditioned spaces. Sensor units in the conditioned spaces provide indications regarding environmental conditions in the conditioned space. The indications are provided using indicating signals provided to a local control unit located in the air terminal device servicing the conditioned space.
The environmental network serves to control at least one Roof-Top Unit (RTU) or other air conditioning unit in providing conditioned air to a duct system. Air terminal devices may control air flow from the duct system to the conditioned spaces.
One or more environmental conditions in a space may be monitored and may be used for controlling conditioning of the space. A temperature sensor may provide an indicating signal relating to temperature within a space. A relative humidity sensor may provide an indicating signal relating to relative humidity within a space. A motion sensor may provide an indicating signal relating to motion occurring within a space, which may be used to indicate that a space is occupied. A carbon dioxide sensor may provide an indicating signal relating to amount of carbon dioxide within a space, which may be used to indicate how many occupants are in a space. One or more of such sensors in addition to other sensors may be employed to condition a space in view of one or more conditions extant within the space.
Situating electronic control units in air terminal devices for responding to indicating signals from sensor units in conditioned spaces locates electronic control units in areas that require service personnel to access duct systems to perform maintenance actions on the electronic control units. Such accessing of duct systems can be inconvenient, uncomfortable and awkward. Positioning electronic control units in air terminal devices also requires locating electronic units in at least two positions—in the air terminal device (in the duct) and in the sensor unit (in the conditioned space). Such a splitting of electronic functionality and equipment can be costly and inefficient as compared to locating electronic units in a single location.
Another consideration in designing an environmental control system is efficiency of communications in a control network associated with such a system. Fewer required notifications, orders and similar communications traversing the network can contribute to more efficient and faster communications. Higher speed and greater efficiency of communication in a control network can contribute to more efficient operation of an environmental control system.
There is a need for an apparatus and method for environmentally conditioning a space that situates electronic control circuitry in easily accessible single locations.
There is a need for an apparatus and method for environmentally conditioning a space that improves efficiency in communications in control network portions of an environmental control system.